org.apache.druid.query.aggregation.first

Class StringFirstBufferAggregator

java.lang.Object

org.apache.druid.query.aggregation.first.StringFirstBufferAggregator

All Implemented Interfaces:

BufferAggregator, HotLoopCallee

public class StringFirstBufferAggregator
extends Object
implements BufferAggregator

Constructor Summary

Constructors

Constructor and Description
StringFirstBufferAggregator(BaseLongColumnValueSelector timeSelector, BaseObjectColumnValueSelector<?> valueSelector, int maxStringBytes, boolean needsFoldCheck)

Method Summary

Modifier and Type	Method and Description
void	aggregate(ByteBuffer buf, int position) Aggregates metric values into the given aggregate byte representation Implementations of this method must read in the aggregate value from the buffer at the given position, aggregate the next element of data and write the updated aggregate value back into the buffer.
void	close() Release any resources used by the aggregator
Object	get(ByteBuffer buf, int position) Returns the intermediate object representation of the given aggregate.
double	getDouble(ByteBuffer buf, int position) Returns the double representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value.
float	getFloat(ByteBuffer buf, int position) Returns the float representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value.
long	getLong(ByteBuffer buf, int position) Returns the long representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value.
void	init(ByteBuffer buf, int position) Initializes the buffer location Implementations of this method must initialize the byte buffer at the given position Implementations must not change the position, limit or mark of the given buffer This method must not exceed the number of bytes returned by AggregatorFactory.getMaxIntermediateSizeWithNulls() in the corresponding AggregatorFactory
void	inspectRuntimeShape(RuntimeShapeInspector inspector) Implementations of this method should call inspector.visit() with all fields of this class, which meet two conditions: 1.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.druid.query.aggregation.BufferAggregator

isNull, relocate

Constructor Detail

StringFirstBufferAggregator

public StringFirstBufferAggregator(BaseLongColumnValueSelector timeSelector,
                                   BaseObjectColumnValueSelector<?> valueSelector,
                                   int maxStringBytes,
                                   boolean needsFoldCheck)

Method Detail

init

public void init(ByteBuffer buf,
                 int position)

Description copied from interface: BufferAggregator

Initializes the buffer location Implementations of this method must initialize the byte buffer at the given position Implementations must not change the position, limit or mark of the given buffer This method must not exceed the number of bytes returned by AggregatorFactory.getMaxIntermediateSizeWithNulls() in the corresponding AggregatorFactory

Specified by:

init in interface BufferAggregator

Parameters:

buf - byte buffer to initialize

position - offset within the byte buffer for initialization

aggregate

public void aggregate(ByteBuffer buf,
                      int position)

Description copied from interface: BufferAggregator

Aggregates metric values into the given aggregate byte representation Implementations of this method must read in the aggregate value from the buffer at the given position, aggregate the next element of data and write the updated aggregate value back into the buffer. Implementations must not change the position, limit or mark of the given buffer

Specified by:

aggregate in interface BufferAggregator

Parameters:

buf - byte buffer storing the byte array representation of the aggregate

position - offset within the byte buffer at which the current aggregate value is stored

get

public Object get(ByteBuffer buf,
                  int position)

Description copied from interface: BufferAggregator

Returns the intermediate object representation of the given aggregate. Converts the given byte buffer representation into an intermediate aggregate Object Implementations must not change the position, limit or mark of the given buffer. The object returned must not have any references to the given buffer (i.e., make a copy), since the underlying buffer is a shared resource and may be given to another processing thread while the objects returned by this aggregator are still in use. If the corresponding AggregatorFactory.combine(Object, Object) method for this aggregator expects its inputs to be mutable, then the object returned by this method must be mutable.

Specified by:

get in interface BufferAggregator

Parameters:

buf - byte buffer storing the byte array representation of the aggregate

position - offset within the byte buffer at which the aggregate value is stored

Returns:

the Object representation of the aggregate

getFloat

public float getFloat(ByteBuffer buf,
                      int position)

Description copied from interface: BufferAggregator

Returns the float representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value. Implementations must not change the position, limit or mark of the given buffer Implementations are only required to support this method if they are aggregations which have an AggregatorFactory.getIntermediateType() ()} of ValueType.FLOAT. If unimplemented, throwing an UnsupportedOperationException is common and recommended.

Specified by:

getFloat in interface BufferAggregator

Parameters:

buf - byte buffer storing the byte array representation of the aggregate

position - offset within the byte buffer at which the aggregate value is stored

Returns:

the float representation of the aggregate

getLong

public long getLong(ByteBuffer buf,
                    int position)

Description copied from interface: BufferAggregator

Returns the long representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value. Implementations must not change the position, limit or mark of the given buffer Implementations are only required to support this method if they are aggregations which have an AggregatorFactory.getIntermediateType() of of ValueType.LONG. If unimplemented, throwing an UnsupportedOperationException is common and recommended.

Specified by:

getLong in interface BufferAggregator

Parameters:

buf - byte buffer storing the byte array representation of the aggregate

position - offset within the byte buffer at which the aggregate value is stored

Returns:

the long representation of the aggregate

getDouble

public double getDouble(ByteBuffer buf,
                        int position)

Description copied from interface: BufferAggregator

Returns the double representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value. Implementations must not change the position, limit or mark of the given buffer Implementations are only required to support this method if they are aggregations which have an AggregatorFactory.getIntermediateType() of of ValueType.DOUBLE. If unimplemented, throwing an UnsupportedOperationException is common and recommended. The default implementation casts BufferAggregator.getFloat(ByteBuffer, int) to double. This default method is added to enable smooth backward compatibility, please re-implement it if your aggregators work with numeric double columns.

Specified by:

getDouble in interface BufferAggregator

Parameters:

buf - byte buffer storing the byte array representation of the aggregate

position - offset within the byte buffer at which the aggregate value is stored

Returns:

the double representation of the aggregate

close

public void close()

Description copied from interface: BufferAggregator

Release any resources used by the aggregator

Specified by:

close in interface BufferAggregator

inspectRuntimeShape

public void inspectRuntimeShape(RuntimeShapeInspector inspector)

Description copied from interface: BufferAggregator

Implementations of this method should call inspector.visit() with all fields of this class, which meet two conditions: 1. They are used in methods of this class, annotated with CalledFromHotLoop 2. They are either: a. Nullable objects b. Instances of HotLoopCallee c. Objects, which don't always have a specific class in runtime. For example, a field of type Set could be HashSet or TreeSet in runtime, depending on how this instance (the instance on which inspectRuntimeShape() is called) is configured. d. ByteBuffer or similar objects, where byte order matters e. boolean flags, affecting branch taking f. Arrays of objects, meeting any of conditions a-e.

The default implementation inspects nothing. Classes that implement BufferAggregator are encouraged to override this method, following the specification of HotLoopCallee.inspectRuntimeShape(org.apache.druid.query.monomorphicprocessing.RuntimeShapeInspector).

Specified by:

inspectRuntimeShape in interface BufferAggregator

Specified by:

inspectRuntimeShape in interface HotLoopCallee